Turbocharger Lubrication Feed Adapter

ABSTRACT

A fitting or adapter for attaching connecting an oil feed tube to a bearing housing of a turbocharger includes a body having a cylindrical sidewall with a central through-channel and an annular groove on an outside thereof for holding a seal ring, such as an O-ring. The sidewall has a plurality of radial holes, the holes spaced apart around a circumference of the cylindrical body and each connecting the central channel and the groove. The radial holes each can have a diameter of between ¼ and ⅓ of a width of the groove taken along an axial direction of the cylindrical sidewall.

FIELD OF THE INVENTION

The present invention relates to turbochargers for internal combustion engines and more particularly to a simplified assembly of and arrangement for lubricating the bearing system of a turbocharger.

BACKGROUND OF THE INVENTION

Turbochargers are widely used on internal combustion engines, and particularly used on large diesel engines, especially for highway trucks. Turbochargers are driven by the engine exhaust gases. Exhaust gases are directed to and drive a turbine, and the turbine shaft is connected to and drives the compressor. The compressor compresses ambient air and feeds the compressed air into the intake manifold of the engine.

The turbine shaft is typically supported on two bearings within a central housing between the turbine and the compressor. Lubricating oil is supplied through a port in the central housing wall and split through oil channels to feed both bearings. Turbochargers commonly use crankcase oil to lubricate the rotating bearing interfaces as well as the thrust surfaces that limit axial excursions of the shaft and its turbine and compressor wheels.

Some examples of turbochargers and bearing lubrication systems can be found in U.S. Pat. Nos. 6,709,160; 4,902,144; 6,418,722 and 5,076,766, herein incorporated by reference.

On some turbochargers, the oil inlet connection comprises a cylindrical fitting or adapter that is surrounded by an o-ring. The cylindrical fitting is fit into the inlet opening and held there by a clamp fixture that is bolted to the center housing. An oil delivery tube is pressed into the fitting and seal welded or brazed thereto.

Resilient seal ring materials, such as elastomeric O-ring materials, have temperature limitations. For example, for VITON or fluoroelastomer material, according to the material specifications, the recommended high temperature limit is 400 degrees F. While the temperature around the O-ring is below this limit during normal operating conditions, it is possible that for some applications, for a short duration immediately after an engine is shut down the temperature around the o-ring could exceed this limit.

SUMMARY

According to an exemplary embodiment of the invention, one or more small holes are added to a turbocharger oil inlet tube fitting or adapter through a groove that holds a seal ring, such as an O-ring, so that the oil passing through the tube also reduces the temperature of the seal ring during engine operation by the oil quenching or flowing over the seal ring during operation. The holes are located closer to the bottom edge of the groove to maintain a leak free joint.

The adapter should provide a reduced operating temperature for the seal ring for normal operating conditions and should prevent excessive temperature after shut down of the engine.

Generally, the disclosed embodiment of the invention provides a fitting for attaching one conduit to another conduit. The fitting includes a body having a cylindrical sidewall with a central through-channel and an annular groove on an outside thereof for holding a seal ring, such as an O-ring. The sidewall has at least one radial hole connecting the central channel and the groove. The at least one radial hole can comprise a plurality of radial holes, the holes spaced apart around a circumference of the cylindrical body. The radial holes each can have a diameter of between ¼ and ⅓ of a width of the groove taken along an axial direction of the cylindrical sidewall.

The embodiment is particularly suited to connecting an oil feed tube to a bearing housing of a turbocharger.

Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevation view, taken in section, of a turbocharger incorporating a lubrication tube fitting in accordance with an exemplary embodiment of the invention;

FIG. 2 is a fragmentary perspective view of a lubrication tube assembly taken from FIG. 1;

FIG. 3 is a side view of the lubrication tube assembly of FIG. 2, removed from the turbocharger, with an o-ring removed to show underlying features;

FIG. 4 is a side view of a lubrication tube fitting taken from FIG. 3; and

FIG. 5 is a sectional view taken generally along line 5-5 of FIG. 4 with the o-ring added.

DETAILED DESCRIPTION

While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.

A turbocharger assembly 20 is shown generally in FIG. 1. The assembly includes a turbine housing 22, a compressor housing 24, and a bearing or center housing 26 disposed between the turbine and compressor housings.

A turbine wheel 30 is fixed on a shaft 32 with the turbine wheel 30 surrounded by the turbine housing 22 and the shaft 32 extending through the bearing housing 26 and into the compressor housing 24. A compressor wheel 36 is mounted on the shaft 32 in the compressor housing 24.

The bearing housing 26 has a central bore 40 that includes bearing lands 44, 46. To rotationally support the shaft 32 and the turbine and compressor wheels, a pair of bearings 50, 52 are received in the bearing lands 44, 46, respectively.

In order to lubricate the bearing system described above, a lubricant, which is normally engine crankcase lubricating oil, is introduced under pressure through a lubricant inlet port 54 formed in the bearing housing 26. The inlet port 54 is a simple straight bore in the housing 26 that communicates with the central bore 40 in the bearing housing.

From the inlet port 54, lubricant migrates axially outwardly along the shaft 32 in both axial directions in the space between the shaft 32 and the central bore 40 toward the journal bearings 50, 52. When the lubricant reaches the journal bearings 50, 52, it is constrained to flow through a plurality of flow paths around the journal bearings and into a pair of oil collection spaces 56, 58 and from there into an oil collection sump 60 where it is returned to the engine crankcase in a conventional manner.

As shown in FIGS. 1-5, an inlet tube fitting 70 is fit into the inlet port 54 and sealed against an inside wall of the port by a seal ring, such as an O-ring 76. The inlet tube fitting 70 is fixed into the port 54 by a separate retaining clamp 78 that has a collar end portion 80 with a hole 82 that receives the tube fitting 70. The collar end portion closely surrounds a socket end portion 86 and presses down against a shoulder 84 of the tube fitting 70 when an anchor leg 88 of the clamp 78 is fastened to the center housing 26 by a machine screw or bolt 94.

The inlet tube fitting 70 includes a groove 102 for receiving a seal ring, formed between a barrel portion 104 and a head portion 106 of the inlet tube fitting 70. The socket end portion 86 includes a tube-receiving socket 110 that is open into a central channel 114 of the fitting 70.

As shown in FIGS. 1-3 a conduit such as a tube 118 is tightly pressed into the socket and brazed, welded or otherwise sealed all around a circular outside interface 122 between the tube 118 and the socket end portion 86. Lubricating oil flows through the tube 118, through the central channel 114 and into the port 54. The compressed O-ring 76 seals the oil flow within the central housing 26.

According to an exemplary embodiment of the invention, at least one radial hole 128 is provided through the fitting 70 within the groove 102. According to the illustrated embodiment, four such holes 128 are provided, rotationally spaced apart at 90 degrees about a central axis 130 of the fitting 70.

According to the illustrated embodiment, the holes 128 can have a diameter of about one third to one fourth of a width of the groove 102, taken along the axis 130. The number of holes and the diameter of the holes can be varied and are still encompassed by the invention.

From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. 

The invention claimed is:
 1. An oil inlet fitting for a turbocharger, comprising: a body having a cylindrical sidewall with a central through-channel and an annular groove on an outside thereof for holding an seal ring, the sidewall having at least one radial hole connecting the central channel and the groove.
 2. The fitting according to claim 1, wherein the at least one radial hole comprises four radial holes that are spaced apart around a circumference of the cylindrical sidewall and each radial hole connects the central channel and the groove.
 3. The fitting according to claim 1, comprising an O-ring fit into the groove.
 4. The fitting according to claim 3, wherein the at least one radial hole comprises four radial holes that are spaced apart around a circumference of the cylindrical sidewall and each radial hole connects the central channel and the groove.
 5. The fitting according to claim 1, wherein the radial hole has a diameter of between ¼ and ⅓ of a width of the groove taken along an axial direction of the cylindrical sidewall.
 6. The fitting according to claim 5, wherein the at least one radial hole comprises a plurality of radial holes that are spaced apart around a circumference of the cylindrical body and each radial hole connects the central channel and the groove.
 7. The fitting according to claim 1, wherein the at least one radial hole comprises a plurality of radial holes that are spaced apart around a circumference of the cylindrical body and each radial hole connects the central channel and the groove.
 8. The fitting according to claim 7, wherein each of the radial holes has a diameter of between ¼ and ⅓ of a width of the groove taken along an axial direction of the cylindrical sidewall.
 9. The fitting according to claim 7, wherein the body includes a socket at one end for attachment of a tube, the tube being open into the central channel.
 10. The fitting according to claim 1, wherein the body includes a socket at one end for attachment of a tube, the tube being open into the central channel.
 11. A fitting for attaching one conduit to another conduit, comprising: a body having cylindrical sidewall with a central through-channel and an annular groove on an outside thereof for holding an seal ring, the sidewall having at least one radial hole connecting the central channel and the groove.
 12. The fitting according to claim 11, wherein the at least one radial hole comprises four radial holes spaced apart around a circumference of the cylindrical sidewall.
 13. The fitting according to claim 11, comprising an O-ring fit into the groove.
 14. The fitting according to claim 11, wherein the radial hole has a diameter of between ¼ and ⅓ of a width of the groove taken along an axial direction of the cylindrical sidewall.
 15. The fitting according to claim 14, wherein the at least one radial hole comprises a plurality of radial holes that are spaced apart around a circumference of the cylindrical body and each radial hole connects the central channel and the groove.
 16. The fitting according to claim 11, wherein the at least one radial hole comprises a plurality of radial holes that are spaced apart around a circumference of the cylindrical body and each radial hole connects the central channel and the groove.
 17. The fitting according to claim 16, wherein each of the radial holes has a diameter of between ¼ and ⅓ of a width of the groove taken along an axial direction of the cylindrical sidewall. 